go-chi
`middlewear.Recover` causes undefined behaviour if a connection has been upgraded.
The middlewear.Recover method attempts to write an HTTP 500 Internal Server Error to a response as part of the error recovery process. This will cause apparently undefined behavior if the connection has been hijacked.
In our use case, we have upgraded our connection to a WebSocket using golang.org/x/net/websocket/websocket.Handler to hijack the connection. A bug in our WebSocket handler, specifically a null pointer error, cause Chi to call Recover. The attempt to write to the upgraded connection after hijack caused apparently undefined behaviour: Internal variables were written down the WebSocket to the client, and the Go runtime reported a generic panic, reducing the diagnosting use of the Recover method.
Can we suggest the Recover method test if the connection has been upgraded or hijacked, and alter it's behavior appropriate - for example not trying to write to the HTTP connection, and possible providing an error over the WebSocket?
Great find and idea. I won’t have time for this one for a while but feel free to PR if you’re interested
On Sep 23, 2021, at 1:05 AM, H Paterson @.***> wrote:
The middlewear.Recover method attempts to write an HTTP 500 Internal Server Error to a response as part of the error recover process. This will cause apparently undefined behavior if the connection has been hijacked.
In our use case, we have upgraded our connection to a WebSocket using golang.org/x/net/websocket/websocket.Handler to hijack the connection. A bug in our WebSocket handler, specifically a null pointer error, cause Chi to call Recover. The attempt to write to the upgraded connection after hijack caused apparently undefined behaviour: Internal variables were written down the WebSocket to the client, and the Go runtime reported a generic panic, reducing the diagnosting use of the Recover method.
Can we suggest the Recover method test if the connection has been upgraded or hijacked, and alter it's behavior appropriate - for example not trying to write to the HTTP connection, and possible providing an error over the WebSocket?
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